4,319 research outputs found

    Deliberative Constitutionalism in the National Security Setting

    Get PDF
    Deliberative democracy theory maintains that authentic deliberation about matters of public concern is an essential condition for the legitimacy of political decisions. Such deliberation has two features. The first is deliberative rigor. This is deliberation guided by public-regarding reasons in a process in which persons are genuinely open to the force of the better argument. The second is transparency. This requires that requires that officials publicly explain the reasons for their decisions in terms that citizens can endorse as acceptable grounds for acting in the name of the political community. Such requirements would seem to be especially important in the national security setting, where decisions can have profound life-and-death consequences. Yet this is the setting in which transparency often is least feasible on the part of the Executive branch. Officials may be constrained for good reasons from fully explaining the bases for their decisions. While such reason-giving is especially important to the perceived legitimacy of a decision, anticipating the need to provide it also can enhance deliberative rigor. Limited transparency thus creates the risk both that crucial decisions may not be regarded as legitimate, and that the deliberative process will not be as robust as it should be. In this chapter, we argue that ensuring robust internal deliberative processes in the national security setting can compensate at least to some degree for this limitation. Appreciating the demands of deliberative democracy theory can help inform this process by illuminating how various procedural mechanisms may promote the goals that transparency purports to serve. We focus on the Lawyers Group, which includes senior national security lawyers from across the government, as an example of an arrangement that can help further the ends of deliberative democracy by providing a vehicle for deliberation that meets many, even if not all, of the requirements of that theory. Coordinated by the legal advisor for the National Security Council, this group discusses national security issues that will be presented to the President. We regard our analysis as contributing in two ways to deliberative democratic theory. First, it focuses on the possibility of satisfying the requirement of this theory in a setting in which decision-making often falls short of the demands of full transparency. Second, it suggests how legal analysis may play a distinctive role in the deliberative process. There are limits to what the Lawyers Group can accomplish. We believe, however, that it should be assessed in terms of its contribution to the larger national security deliberative system of which it is a part. From this perspective, the Group’s compliance with several prescriptions of deliberative theory helps it strengthen, even if it does not guarantee, the rigor and persuasiveness of the justifications that the President is able to provide for national security decisions

    Thermometry of Silicon Nanoparticles

    Full text link
    Current thermometry techniques lack the spatial resolution required to see the temperature gradients in typical, highly-scaled modern transistors. As a step toward addressing this problem, we have measured the temperature dependence of the volume plasmon energy in silicon nanoparticles from room temperature to 1250∘^\circC, using a chip-style heating sample holder in a scanning transmission electron microscope (STEM) equipped with electron energy loss spectroscopy (EELS). The plasmon energy changes as expected for an electron gas subject to the thermal expansion of silicon. Reversing this reasoning, we find that measurements of the plasmon energy provide an independent measure of the nanoparticle temperature consistent with that of the heater chip's macroscopic heater/thermometer to within the 5\% accuracy of the chip thermometer's calibration. Thus silicon has the potential to provide its own, high-spatial-resolution thermometric readout signal via measurements of its volume plasmon energy. Furthermore, nanoparticles in general can serve as convenient nanothermometers for \emph{in situ} electron microscopy experiments.Comment: 6 pages, 3 figure

    CP Violation from a Higher Dimensional Model

    Get PDF
    It is shown that Randall-Sundrum model has the EDM term which violates the CP-symmetry. The comparison with the case of Kaluza-Klein theory is done. The chiral property, localization, anomaly phenomena are examined. We evaluate the bulk quantum effect using the method of the induced effective action. This is a new origin of the CP-violation.Comment: 15pages, Proc. of Int. Workshop on "Neutrino Masses and Mixings"(Dec.17-19,2006,Univ.of Shizuoka,Japan

    Tree-level electron-photon interactions in graphene

    Full text link
    Graphene's low-energy electronic excitations obey a 2+1 dimensional Dirac Hamiltonian. After extending this Hamiltonian to include interactions with a quantized electromagnetic field, we calculate the amplitude associated with the simplest, tree-level Feynman diagram: the vertex connecting a photon with two electrons. This amplitude leads to analytic expressions for the 3D angular dependence of photon emission, the photon-mediated electron-hole recombination rate, and corrections to graphene's opacity πα\pi \alpha and dynamic conductivity πe2/2h\pi e^2/2 h for situations away from thermal equilibrium, as would occur in a graphene laser. We find that Ohmic dissipation in perfect graphene can be attributed to spontaneous emission.Comment: 5 pages, 3 figure

    Electron tomography at 2.4 {\AA} resolution

    Full text link
    Transmission electron microscopy (TEM) is a powerful imaging tool that has found broad application in materials science, nanoscience and biology(1-3). With the introduction of aberration-corrected electron lenses, both the spatial resolution and image quality in TEM have been significantly improved(4,5) and resolution below 0.5 {\AA} has been demonstrated(6). To reveal the 3D structure of thin samples, electron tomography is the method of choice(7-11), with resolutions of ~1 nm^3 currently achievable(10,11). Recently, discrete tomography has been used to generate a 3D atomic reconstruction of a silver nanoparticle 2-3 nm in diameter(12), but this statistical method assumes prior knowledge of the particle's lattice structure and requires that the atoms fit rigidly on that lattice. Here we report the experimental demonstration of a general electron tomography method that achieves atomic scale resolution without initial assumptions about the sample structure. By combining a novel projection alignment and tomographic reconstruction method with scanning transmission electron microscopy, we have determined the 3D structure of a ~10 nm gold nanoparticle at 2.4 {\AA} resolution. While we cannot definitively locate all of the atoms inside the nanoparticle, individual atoms are observed in some regions of the particle and several grains are identified at three dimensions. The 3D surface morphology and internal lattice structure revealed are consistent with a distorted icosahedral multiply-twinned particle. We anticipate that this general method can be applied not only to determine the 3D structure of nanomaterials at atomic scale resolution(13-15), but also to improve the spatial resolution and image quality in other tomography fields(7,9,16-20).Comment: 27 pages, 17 figure

    Polarized light emission from individual incandescent carbon nanotubes

    Full text link
    We fabricate nanoscale lamps which have a filament consisting of a single multiwalled carbon nanotube. After determining the nanotube geometry with a transmission electron microscope, we use Joule heating to bring the filament to incandescence, with peak temperatures in excess of 2000 K. We image the thermal light in both polarizations simultaneously as a function of wavelength and input electrical power. The observed degree of polarization is typically of the order of 75%, a magnitude predicted by a Mie model of the filament that assigns graphene's optical conductance πe2/2h\pi e^2/2 h to each nanotube wall.Comment: 5 pages, 4 figure
    • …
    corecore